Simulated circuit breaker teaching device



Feb. 16, 1960 F. M. sALlsBURY 2,924,890

SIMULATED CIRCUIT BREAKER TEACHING DEVICE Filed March 3l. 1958 UnitedStates Patent O SINIULATED CIRCUIT BREAKER TEACHING DEVICE Frank M. Salisbury, Bulalo, N.Y., assignor to Carmody Corporation, Buffalo, N.Y.

Application March 31, 195s, serial No. 724,919

6 claims. (cl. '3s-1o) This invention relates to a simulated circuit breaker teaching device consisting primarily of aA simulated, students circuit breaker which controls a students signal device and is so arranged that the instructor may remotely control in various manners the actuation of said circuit breaker, and thereby control both said circuit breaker and also the students signal device which is dominated by said circuit breaker.

The main object of the invention is to provide a teaching device which includes a simulated students circuit. breaker and which will teach him what to do and howA to4 analyze the diierent signiiicances in the action of said circuit breaker when the latter, in simulated fashion, is wired to a simulated piece of apparatus which the student is to be taught to control. Other objects of the invention and practical solutions thereof are described in detail in the following specification and are illustrated in the accompanying drawing, wherein:

The sole figure in the accompanying drawing diagrammatically illustrates a teaching device which includes a. simulated circuit breakerV in combination with a simu lated student signal device.

`ForI convenience this invention will be described exactly as it is illustrated, but it is to be understood that the scope of the invention is to be measured solely by its intrinsic novelty and by the scope of the appended. claims.

Let us assume that the student who is being taught by the instructor is an embryonic aviator and that he is being taught to properly decide which of several actions to take under various conditions which arise inv actual practice in association with a specific piece of' apparatus, such as the nose wheel of an airplane. Let us also assume that he has been previously instructed that, when one certain students signal device, such as the electric lamp bulb 2 is lit, the aforesaid nose wheelA is in one of its correct positions, in, for instance, its fully retracted position.

This students signal device 2 in this simulated set-up,l is wired in series through wires 3 and 4 to a battery or other source of power 5 connected to a wire 6. The: wires 4 and 6 are connected, respectively, through lead. wires 7 and 8 to the terminals 10 and 11 of a students automatic switch 12 of a simulated circuit breaker A. This switch 12 is preferably a micro switch and is suitably secured to the frame 28 of said circuit breaker' A and is provided with a switch blade 13 and a switch. contact 14, the former of which is so formed as to resiliently be urged at its upper end out of contact (to the left) or away from said switch contact 14. In the position of the circuit breaker A shown in the drawing: this resilient urge of the switch blade 13 is restrained by a spring-actuated finger 15 whose spring actuation is derived from the resiliency of said switch blade 13. This restraint upon the spring-actuated nger 15, in this position of the circuit breaker A, is provided by a sha1- low shoulder 16 which is formed semi-annularly in the upper, outer surface of a cup-shaped sleeve 17.

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This sleeve 17V is secured by a set screw 18 to the lower end of a slide rod or vertically movable core 20 whose extreme upper end is threaded at 21 to receive an operating knob 22. Secured to the lower end of said operating knob 22 is a colored danger indicating collar 23 which, in the position of the circuit breaker A shown in the drawing, is concealed from view by an upstanding annular concealing flange 24 whose lower end is threaded to an annular head 25 which forms the upper end of a solenoid 26 that is encased in a metal tube 27. By this means, both said concealing flange 24 and said solenoid 26 are secured to the sheet metal frame 28 of the circuit breaker A.

In the position of said circuit breaker A as shown in the drawing, the operating knob 22 is in its extreme lower position, and the indicating collar 23 is completely concealed by the concealing ange 24. In this position also, the students signal device (incandescent bulb 2) is lit, and, from this latter fact, plus the fact that the danger indicating collar 23 is invisible, informs the student that his nose wheel is fully retracted, and that all is presumably well with respect to its entire retracting apparatus.

Arranged on the left side of the frame 28 of the simulated circuit breaker A, and suitably secured thereto, is an instructors automatic switch 121 which is preferably identical in all respects to the students automatic switch 12. This switch 121 has a switch blade 131 and a switch contact 141 which are electrically connected, respectively, to terminals 101 and 111. In the position of the circuit breaker A shown in the drawing, the springactuated nger 151 engages the same semi-annular shallow shoulder 16 as is engaged by the spring-actuated linger 15 of the students automatic switch 12.

The intermediate terminal 111 of the switch contact 141 is connected by a lead Wire 30 to the solenoid 26, and the latter is connected by a lead wire 31 with an instructors switch 32. The latter is grounded at 34. The terminal 101 of switch blade 131 connects through wires 35 and 36 to a source of power 33 and the ground at 37.

Hence, when the instructor closes his switch 32, the solenoid 26 is activated and the sleeve 17 and operating knob 22 moved to their extreme upper positions as shown by the dotted lines for the upper positions of the operating knob 22 and sleeve 17.

The instructors automatic switch *121 (like the students automatic switch 12) is provided with a secondary switch contact 38 whose terminal 40 is connected by a -wire 41 to the instructors ott electric light bulb or other signal device 42 and thence, through wire 43 to the ground at 44.

It should be noted, at this time, that the core 20 of solenoid 26 is prevented mechanically from vibrating out of the position shown in the drawing, i.e., when the instructors switch 32 is open. This is because downward movement of the core 20 is prevented by the contact of the lower face of the operating knob 22 upon the top face of the xed, annular head 25. Upward accidental movement of said core 20 is mechanically prevented by the engagement of the spring-actuated fingers 15 and 151 with the horizontal face of the shallow shoulder 16 of sleeve 17.

When the instructor closes his switch 32, the solenoid 26 is immediately energized and the sleeve 17 moved to its uppermost position. This causes the springactuated fingers 15 and 151 of the automatic switches 12 and 121 to be pushed out of the shallow shoulder 16 of said sleeve 17. Thereupon said fingers 15 and 151 resiliently thrust themselves into a deep groove 45 which is formed semi-annularly near the lower end of the sleeve 17. This simultaneously allows the switch blades 13 and 131 to resiliently 'move away from their respective switch contacts 14 and 141. This cuts oi the current through the students signal device 2 and is an indication to him that something is wrong. It also closes the circuit between the switch blade 131 and the switch contact 3S of the instructors automatic switch 121 and lights his oit electric light bulb or signal device 42.

and hence indicates to the instructor that the operating knob 22 of circuit breaker' A is in its danger or off position. Furthermore, this operating knob Z2 will mechanically stay in this position, despite any ordinary vibration, because the deep groove 45 resiliently engages the spring-actuated fingers 15 and 151 and thereby prevents accidental downward movement of the sleeve 17. Upward movement is prevented by the contacting of sleeve 17 and with the bottom of solenoid casing 27.

If the instructor then takes his finger oi of his switch 32, the student, if he acts correctly, will notice that his nose wheel retracting light or signal device 2 is out, and will then conclude that there has probably Ibeen a temporary short circuit which has tripped the circuit breaker A. If he acts correctly, he will then reach over and push in the operating knob 22 and the latter will stay in under these conditions and this will mean that all is well again.

Suppose, however, that the instructor wishes to simulate a permanent short circuit in the nose wheel electric circuit, or perhaps some mechanical trouble. To eect this simulated condition, the instructor not only closes his switch 32 but holds it closed. If thestudent then acts correctly, he will at first assume that the short circuit is due to a surge and is only temporary. He will, accordingly, push in the operating knob 22 of his circuit breaker A. However, with the instructor holding the switch 32 down, said operating knob 22 will not stay in but will again jump out as soon as the student lets it go. The student then will conclude, if he acts correctly, that something is fundamentally wrong and he will take steps to either have the nose wheel cranked in by hand or take other appropriate action.

It should be added that the colored indicating collar 23 usually has one or more words or symbols printed or engraved on one of its sides. Hence, it is ydesirable to u prevent any rotation of this collar 23 together with the core v20 and itsV operating knob 22. This desired result is accomplished by flattening the one face of the sleeve =`17 at 46 which flat face rides against the flat inner face of the front plate (not shown) of the circuit breaker A.

Iclaim: 1. A simulated circuit breaker teaching device comprising: a solenoid having a movable core; a sleeve connected with said core and having a shallow shoulder and a deep groove spaced longitudinally thereof; an instructors automatic switch having a spring-actuated finger which controlsv said switch and engages either said shoulderor said groove, said instructors switch being connected in series with said solenoid and also a source of power and an instructors control switch; and a students automatic switch also having a spring-actuated nger which engages said shoulder` or said groove, said students switch being connected in series with a source of power and a students signal device.

2. A simulated circuit breaker teaching device as in claim 1 with the instructors automatic switch having a pair of contacts one of which is wired in series with an off signal device.

`3. A simulated circuit breaker teaching device as in claim l with the shoulder and the groove being annular.

4. A simulated circuit breaker teaching device as in claim l with the shouldery and the groove being annular and with the two automatic switches being located on opposite sides of the sleeve.

5.'A simulated circuit breaker teaching device as in claim l With the solenoid core consisting of a rod secured at its lower end to the sleeve and secured at its upper end to an operating knob having an indicating collar.

6. A simulated circuit breaker teaching device as in claim 1 with the shallow shoulder disposed perpendicularlyof the axis ofthe core. f

References Cited in the le of this patent UNITED STATES PATENTS' 

